20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_MEMORY_MODREFBARRIERSET_HPP
  26 #define SHARE_VM_MEMORY_MODREFBARRIERSET_HPP
  27 
  28 #include "memory/barrierSet.hpp"
  29 
  30 // This kind of "BarrierSet" allows a "CollectedHeap" to detect and
  31 // enumerate ref fields that have been modified (since the last
  32 // enumeration), using a card table.
  33 
  34 class OopClosure;
  35 class Generation;
  36 
  37 class ModRefBarrierSet: public BarrierSet {
  38 public:
  39 
  40   ModRefBarrierSet() { _kind = BarrierSet::ModRef; }
  41 
  42   bool is_a(BarrierSet::Name bsn) {
  43     return bsn == BarrierSet::ModRef;
  44   }
  45 
  46   // Barriers only on ref writes.
  47   bool has_read_ref_barrier() { return false; }
  48   bool has_read_prim_barrier() { return false; }
  49   bool has_write_ref_barrier() { return true; }
  50   bool has_write_prim_barrier() { return false; }
  51 
  52   bool read_ref_needs_barrier(void* field) { return false; }
  53   bool read_prim_needs_barrier(HeapWord* field, size_t bytes) { return false; }
  54   bool write_prim_needs_barrier(HeapWord* field, size_t bytes,
  55                                 juint val1, juint val2) { return false; }
  56 
  57   void write_prim_field(oop obj, size_t offset, size_t bytes,
  58                         juint val1, juint val2) {}
  59 
  60   void read_ref_field(void* field) {}

  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_MEMORY_MODREFBARRIERSET_HPP
  26 #define SHARE_VM_MEMORY_MODREFBARRIERSET_HPP
  27 
  28 #include "memory/barrierSet.hpp"
  29 
  30 // This kind of "BarrierSet" allows a "CollectedHeap" to detect and
  31 // enumerate ref fields that have been modified (since the last
  32 // enumeration), using a card table.
  33 
  34 class OopClosure;
  35 class Generation;
  36 
  37 class ModRefBarrierSet: public BarrierSet {
  38 public:
  39 
  40   ModRefBarrierSet() : BarrierSet(BarrierSet::ModRef) { }
  41 
  42   bool is_a(BarrierSet::Name bsn) {
  43     return bsn == BarrierSet::ModRef;
  44   }
  45 
  46   // Barriers only on ref writes.
  47   bool has_read_ref_barrier() { return false; }
  48   bool has_read_prim_barrier() { return false; }
  49   bool has_write_ref_barrier() { return true; }
  50   bool has_write_prim_barrier() { return false; }
  51 
  52   bool read_ref_needs_barrier(void* field) { return false; }
  53   bool read_prim_needs_barrier(HeapWord* field, size_t bytes) { return false; }
  54   bool write_prim_needs_barrier(HeapWord* field, size_t bytes,
  55                                 juint val1, juint val2) { return false; }
  56 
  57   void write_prim_field(oop obj, size_t offset, size_t bytes,
  58                         juint val1, juint val2) {}
  59 
  60   void read_ref_field(void* field) {}